Re: What were the effects of the atomic bomb on Hiroshima's water,soil,and, air

The question you asked is very general, so I won't try to provide specific 
information on any one aspect of the topic.  

When an atomic bomb detonates in the air, as one did over Hiroshima in 
1945, neutrons from the bomb activate elements in the air, water, and soil 
in close proximity to the explosion.  In addition, radioactive debris from 
the blast settle, or "fallout," onto the surface of the ground, 
vegetation, and water. Neutron activation and fallout were relatively 
minor problems for Hiroshima because of the almost total destruction of 
the city due to blast and fire damage, and the extensive radiation and 
thermal burns of its occupants.

The surviving victims of the blasts over Hiroshima and Nagasaki have been 
extensively studied, in part to learn exactly how much radiation dose they 
received from the blast and the subsequent fallout.  Interestingly, the 
neutron activation of concrete construction materials which still survive 
in the two cities has been used to help establish the neutron dose at 
different distances from the blasts, which has helped to establish the 
total radiation dose to victims at various locations within the two cities.

For technical information on environmental radioactivity, including 
radioactivity from the detonation of atomic bombs, I 
recommend "Environmental Radioactivity," by Merril Eisenbud (3d edition, 
1987, Academic Press).  Unfortunately, Eisenbud does not have a thorough 
treatment of Hiroshima and Nagasaki, specifically.
For a general overview of the history of the blast, visit the WWW A-Bomb 
Museum at: http://www.csi.ad.jp/ABOMB/ind
ex.html
or visit the City of Hiroshima homepage at: http://www.city.hiroshima.jp/

If I may offer a caveat (not specific to the webpages above), lots of dis-
information exist on the web (and elsewhere).  There is lots of good 
information, but I suggest that you confirm the information you find there 
by verifying the information through peer-reviewed journals.